The elderly experience disproportionate illness and death during extreme heat. While elderly migrants have been identified as at risk, vulnerability of ethnic groups is a significant research gap in the heat health field. Ethnic groups are assumed to be homogeneous with consistent heat risks in that population, with differing heat risks not explored below the population level. Overseas heat vulnerability modelling shows a spatial correlation with the presence of minority or migrant groups, low socio-economic status and biophysical risk. Without a clear understanding of what constitutes ethnic heat risk, aggregating and modeling population data becomes problematic and risks missing vulnerable groups in Australia. In some Australian cities heat vulnerability modeling attributes spatial risk to ethnicity, elderly living alone and nursing homes without a biophysical and socio-economic relationship. Using ‘CALD’ to define ethnicity biases research towards new migrants and refugees of low socio-economic status, excluding the Australian-born of migrants. Australian population research using this approach assumes acculturation to be automatic. A case study of an identified highly vulnerable area of the Melbourne Jewish Community explores pre-determined elderly sub-groups, of which 50% are excluded by modeling and CALD approaches. A new methodology to determine ethnic heat risk is proposed by exploring the intersection of biophysical, socio-demographic and cultural heat risks as well as adaptive behaviours at the dwelling of the individual. Two proposed Jewish elderly vulnerable groups have been studied over the 2015/2016 summer: Adult and Child Holocaust Survivors and Former Soviet Union Jews.Preliminary results will be shown in an oral presentation.